Early electrophotographic copiers used a hard metallic fusing roller covered with a fluorocarbon which imparted an undesirably glossy finish to what was nearly 100% textural material. Later copiers used a silicone rubber fusing roller which provided a more matte finish to the text which generally has been considered more desirable.
As electrophotography has become more and more capable of reproducing pictorial subject matter, especially in three or four colors, a desire for a more glossy appearance has been felt. Accordingly, hard metallic fusing surfaces are used and toners are formulated and designed for glossy reproduction for image forming apparatus designed for color pictures. At the same time, office copiers dealing primarily with textural material or graphics continue to prefer a more matte finish.
As apparatus of both types becomes more flexible, pictorial subject matter is more and more being mixed with text and graphics in essentially the same image. Desk top publishing systems are quite capable of combining a scanned color pictorial image with text or graphics from a different source. It has been suggested that the use of black toners which are formulated to give a matte finish in combination with color toners formulated to produce a glossy finish will provide both a matte finish for text and a glossy finish for pictorials at the same fusing conditions of heat and pressure. If undercolor removal is used in the pictorials, black is laid down first and hopefully completely covered by the glossier color toner for most of a pictorial image. See, for example, Japanese Patent Appl. 133422/87, Laid-Open No. 300254/88, Dec. 7, 1988.
If a glossy toner is fused to a less glossy receiving sheet the amount of gloss may vary imagewise, giving an undesirably uneven appearance. It has been suggested that a clear, glossy toner can be added either uniformly or imagewise across the top of a multicolor toner image to increase the gloss of the image. The clear toner can be laid down in an image configuration which will even the height of the toner and the qloss of the image already there or it can be laid down evenly. See, for example, Xerox Disclosure Journal. Volume 16, No. 1, January/February 1991, page 69; and U.S. Pat. No. 4,828,950 issued to R. P. Crandall, May 9, 1989.
The choice between matte, silk or glossy images in conventional photography has been largely considered one of choice to the consumer. That choice is provided in photofinishing by imparting a particular texture or gloss to photographic paper in its manufacture which is eventually imparted to the image after printing.